Prothrombin fragment 1+2 as a sensitive marker of intraventricular thrombus formation in a patient with dilated cardiomyopathy: comparison with echocardiography.

A 50-year-old man with dilated cardiomyopathy was admitted to our hospital due to heart failure symptoms. Although prothrombin fragment 1+2 (F1+2) was significantly elevated, there was no thrombus in the left ventricle by echocardiography. However, anticoagulation therapy was started because of a possibility of thrombus formation. On the 4th day, F1+2 was persistently elevated and echocardiography detected intraventricular thrombi. After surgical removal of thrombi, F1+2 level decreased rapidly. F1+2 elevation preceded echocardiographic detection of intraventricular thrombi. Therefore, when F1+2 is significantly elevated, echocardiography should be performed meticulously and repeatedly to detect a thrombus.